Hydraulic lift for trucks



July 11, 1933. w. SCHROEDER 1,917,602

HYDRAULIC LIFT FOR TRUCKS Filed June 1, 1931 5 Sheets-Sheet 1 July 11, 1933:. w. SCHROEDER HYDRAULIC LIFT FOR TRUCKS Filed June 1, 1931 5 Sheets-Sheet 2 Jab 11 1933, C gDER 1,917,602

HYDRAULIC LIFT FOR TRUCKS Filed June 1; 1931 5 Sheets-Sheet 5 1933- w. SCHROEDER HYDRAULIC LIFT FOR TRUCKS Filed June 1, 1931 5 Sheets-Sheet 4 lllllllllllJ Y .9 9 w. SCHROEDER 1,917,602

I HYDRAULIC LIFT FOR TRUCKS Filed June 1,-1951 5 Sheets-Sheet 5 f .A F fig 6 n UL W 52 \Q,' 1F

Patented July 11, 1933 UNITED STATES PATENT OFFICE WILLIAM SCENE-13m OF CHICAGO, ILLINOIS, ASSIGNOR T0 MERCURY EANUFACTUE- ING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 01' ILLINOIS v HYDRAULIC LIFT FOR TRUCKS Application filed June 1, 1981. Serial No. 541,311.

The present invention relates to a hydraulic lift for trucks and particularly to one applicable for use in a truck of the type having an elevating platform.

An object 'of the present invention is to provide a hydraulic lift for industrial trucks having elevating platforms wherein the platform is maintained in horizontal position irrespective of the manner of placing the load on the platform.

Another object of the invention is to provide a hydraulic lift for trucks of the type having elevating platforms.

A further object of the invention is to provide hydraulic lifts for the elevating platforms of industrial trucks whereby the speed of lowering the platform may be regulated as desired.

A still further object of the invention is to provide hoist mechanism for elevating platforms of industrial trucks wherein the platform is equalized throughout its raising and lowering movements by the hoist mechanism.

Generally speaking the invention contem? plates a hydraulic hoist mechanism for raising and. lowering the platforms of the elevating type of industrial trucks wherein cables are attached to opposite sides of the platform and wherein ahydraulic plunger carries sheaves engaging the cables so that lifting effort is distributed equally to the platform thus preventing tilting or canting of the same during its raising and lowering movements.

The invention further contemplates a hydraulic hoist for elevating platforms of industrial trucks wherein a raising movement is accomplished by pressure and the lowering movement by gravity.

The above, other, and further objects of the invention will be apparent from the following description, accompanying drawings, and appended claims.

Embodiments of the invention are illus trated in the accompanying-drawings and the views thereof are as follows:

Figure 1 is a rear elevational view of an in dustrial truck equipped with the present invention.

Figure 2 is a top plan view, with parts broken away, of the truck illustrated in Figure 1.

Figure 3 is a fragmental top plan view,

artially in section, of the truck illustrated in igure 1 and showing certain details of contaken substantially in the plane of line IVIV of Figure 2.

Figure 5 is a fragmental side elevational view of the upright and hydraulic hoist with a fragmental portion of the platform and showing the manner of mounting the pump in connection with the hoist, and showin in dotted lines the platform in elevated position.

Figure 6 is a fragmental plan view, with parts in section, of portions of the piping circuit.

Figure 7 is a fragmental rear elevational view, with parts in section, showing other details of the piping circuit.

Figure 8 is a side elevational view of a portion of the pipe circuit and illustrating the position of the control valve.

The'drawings will now be explained.

The form of industrial truck chosen to exemplify the present invention is similar to that shown in the copending application of this applicant Serial N 0. 541,309 filed June 1, 1931 and consists of a truck frame designated generally at A and including a pair of channel uprights 1 and 2 arranged with the flanges directed towards each other that is inwardly of the truck and which upri hts are connected at the top by a plate 3 an an inverted channel 4 inserted between the inner ends of the flanges of the upri hts 1 and 2.

The truck carries a battery ox B for containing the electric batteries for operation of the driving motor 5 and the pump motor 6.

Front wheels 7 are provided as well as rear wheels 8 whioh-may be arranged and connected for steering as set forth in copending application above identified.

The elevating platform C is supported on platform side frame members 7 a and 8 which members in turn are provided with top and bottom rollers 9 and 10. The rollers 9 and I 10 of the side frame member 7 are guided length by in the upright channel member 1 and the top and bottom rollers of the platform side frame member 8 are in like manner channel u right.2.- The platform is a cantilever plat orm.

A hydraulic c linder 11 is supported in the truck frame and is provided with a plunger orpiston 12 having a head 13 at its outer end. The head 13 is provided with spaced upstanding ears 14 and 15 supportin a shaft 16 on which are two sheaves 17 an 18 freely rotatable.

A cable 19 has a socket 20 at one end which socket is provided with a bolt portion 21 engaging an apertured lug 22 on the truck frame structure. Nuts 23 cooperate with the bolt portions of the socket for adjusting the cable in the lug. The cable 19 is trained over the sheave 17 with its other end socketed and assed through 2. lug 24 fastened to the plat orm side frame member 7 Another cable 25 has a socket 26 fastened to one end which socket is provided with a bolt portion 27 which enters an apertured lug 28 on the truck frame structure. Nuts 29 are provided for adjustin this end of the cable in the lug 28. The ca le 25, is trained over the sheave 18 and has its other end socketed for engagement with a lug 30 fastened to the platform side frame member 8.

The cables 19 and 25 are adjusted as to means of the nuts at the ends of the socket members where the same engage the several lugs. The cables once having been properly tightened then as the plunger or piston moves upwardly the platform is lifted evenly and held against tiltin or canting no matter where the load may e on the platform.

A pipe circuit is provided for supplying fluid to the cylinder 11 for moving the plungor or iston 12 to raise the'platform C.

A uid reservoir 30 is carried by the truck frame and a ump 31is secured adjacent the reservoir. e pump 31 is driven by a motor 32 carried on the truck and connected to the pump by a shaft 33. An inlet pipe 34 leads from the reservoir 30 to the inlet side of the pump 31.' A drain pipe 35 is interposed between the pump and reservoir 30 to return to the reservoir any leakage fluid there ma be in the pum pipe 35" leads from the outlet side of the motor and into the cylinder 11. A check valve-36 is interposed in this pipe to prevent flow of fluid from the cylinder to the pump. A breather 37 communicates with the interior of the reservoir 30 for admitting atmospheric pressure to the same.

A pipe line 38 leads from the cylinder 11 upwardly near the rear end of the truck and is rovided with a. control valve 39. The va ve is conveniently disposed for the operator who stands on the (platform 40 at the rear of the truck. A han e 41 for the valve 39 guided in the.

to pump T 43 with-the interior ofthe cylinder 11.

A relief valve 46 is interposed in the pipe 45.

The c linder 11 is suitably supported in the true frame and projects thru an openin in a gusset late 47 which is welded to si e frame mem ers 48 and 49 of the truck frame structure. The uprights 1 and 2 are welded to the gusset plate 47.

The platform I) is raised by moving the plunger 12 upwardly in the cylinder 11 and lowered by gravity through manipulation of the fluid control valve 39.

When it is desired to raise the control valve 39 is closed. The motor 32 is energized therebyoperating the pump 31 fluid from the reservoir 30 into the cylinder 11. The pumping of the fluid into the cylinder 11 raises the plunger or piston 12 and at the same time fills the pipe 38 with fluid up to the control valve 39. When the platform has been raised the desired amount the circuit to the motor 32'is opened thus stopping the motor and the pump. Provision of the check valve 36 in the inlet pipe 35 to the cylinder 11 prevents backflow of fluid from the cylinder to the pump consequently the cylinder is supported in raised position by the fluid within the cylinder 11.

The provision of the cables 19 and 25 passing over the sheaves 17 and 18 in opposite directions assures at all times-that the platform D is maintained on an even keel otherwise the platform is prevented'from tilting or canting no matter where the load may be trol valve 39in a direction to open communication between the pipes 38 and 42 of the pipe circuit the amount of opening of the valve controlling the flow of fluid past the same. The opening of the valve 39 allows flow of the li uid or fluid in the cylinder 11 from the cy 'nder through pipe 38, control valve 39, pipe 42to the T 43 thence through the connection 44 into the reservoir. The weight of the platform and its supported load at the elevating mechanism being suificient to cause the plat orm to descend by gravity when the pressure against the plunger or piston 12 is relieved as it is by 39. The speed of lowering is regulated by the amount of opening in the control valve 39. The valve 39 remaining open until the platform descends to its lowermost position causes the platform '1) opening of the control removal of most of the fluid from the cylinder it 11 by the downward movement of the piston 12. Any excess fluid there may be in the pump 31 returns to the reservoir 30 through the pipe 32..

it will be observed that the present invention provides a hoist mechanism for an elevatin platform of an industrial truck which is sucient to raise capacity loads easily and quickly and is arranged to support the platform to prevent tilting or canting of the same. The provision of the sheaves and the arrangement of the cables as before stated tends to equalize the raising pull applied to the platform by the cables.

The truck is steered by means of a steerin bar 50 disposed at the rear end of the true in convenient place for the operator steering being accomplished through steering mechanism such as that described in the copending application above identified.

The invention has been described herein more or less precisely as to details yet it is to be understood that changes may be made in the arrangement and proportion of parts and equivalents may be substituted without departing from the spirit and scope of the invention.

The invention is claimed as follows 1. An industrial truck of the elevating platform type, includingincombination,raising means for the platform of said truck, said raising means including cables having similar ends thereof attached to the sides of the platform on opposite sides of the center line of the platform, sheaves supportedfor bodily movement and also relative rotative movement, said sheaves being disposed with the axes thereof coincident and extending lengthwise of the truck, said cables being trained over said sheaves in op osite directions and having similar ends of t e cables fastened to opposite sides of the platform, the other ends of said cablesbeing fixed against movement, a single vertically movable member carrying said sheaves, means for moving said member in the manner stated, the bodily movement of said sheaves causing raising movement of said platform, the attachment of the cables at the sides of the platform being effective to prevent tilting of the platform in service.

2. An industrial truck of the elevating platform t pe, including in combination, a single vertically movable plunger, two relatively rotatable sheaves on said plunger lying in parallel'planes which are normal to the length of the truck, a platform, a cable trained over one sheave and having one end connected to the truck adjacent one side thereof and the other end of the cable connected to the platform adjacent the opposite side of the truck, a second cable trained over the other of said sheavesand having one end thereof connected to the truck adjacent a side thereof and the other end connected to the platform adjacent the opposite side of the truck, the end of the second cable which is connected to the platform being on the same side of the truck center as the end of the first cable which is connected to the truck, the end of the first cable connected to the platformbeing on the same side of the truck center as the end of the second cable connected to the truck, the latter mentioned ends of the first and second cables being on the op osite sides of the truck center from the opposite ends of said cables.

3. An industrial truck of the elevating platform type, including in combination, a platform, means for raising and lowering said platform, said means comprising a single vertically movable member, two sheaves carried by said member and arranged thereon in parallel relation and with the axes thereof coincident and extending in the direction of the length of the truck, cables passing over said sheaves, each cable having an end attached to said platform and then dead-ended to the truck structure, the cable ends which are attached to the platform being connected thereto on opposite sides of the truck center and the cable ends dead-ended being attached to the truck structure on opposite sides of the truck center from the other ends of the cables for preventing tilting of the platform while being raised and lowered, and means for actuating said vertically movable member.

4. An industrial truck of the elevating platform type, including in combination, a single vertically movable member, two inde pendently rotatable sheaves arranged in side byside relation atop said member, the axis of v rotation of said sheavesintersecting the longitudinal axis of said member, an elevator, cables trained over said sheaves, one end of one cable being fastened to the truck body with the other end of said cable fastened to the elevator on the opposite side of the median line of said body from said one end, the other cable having an end fastened to said elevator on the same side of the median line of the truck body as the one end of said first cable and its other end fastened to the truck body on the same side of the median line as the other end of said first cable, and means for effecting vertical movement of said memher to raise and lower said elevator.

In testimony whereof I have hereunto subscribed my name at Chicago, Cook County,

Illinois.

WILLIAM SCHROEDER. 

